Combination heater and muffler



Aug. 21, 1956 A. B. CHAPMAN ET AL 2,759,709 COMBINATION HEATER ANDMUFFLER I5 Sheets-Sheet 1 Filed Sept. 29, 195s 21, 1956 A. B. CHAPMAN ETAL 2,759,709

' COMBINATION HEATER Ayn MUFFLER Fi led'Sept. 29, 1953 w s Sheet-Sheet.2

M Ga ATTORNEY 21, 1956 A. B. CHAPMAN ET AL 2,759,709

COMBINATION HEATER AND MUFFLER 5 Sheets-She t- 5 Filed Sept. 29, 1953 If INVENTORS Q/iez/fi.

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United States Patent @fliee COMBINATION HEATER AND MUFFLER Albert B.Chapman, Robert P. McDonough, and William H. Jackson, Lockport, N. Y.,assignors to General Motors Corporation, Detroit, Mich, a corporation ofDelaware Application September 29, 1953, Serial No. 383,105 21 Claims.(Cl. 257-16) This invention relates to heaters for fluids and moreparticularly to combinations of heaters and mufllers in units of suchcompactness and eificiency as to make them suitable for use in vehicles.

Two convenient forms of construction are hereinafter described asexamples embodying features of the present invention. in each of theseforms, provision is made whereby an efficient heat exchange may be hadbetween a heated fluid such as the exhaust gases from an internalcombustion engine and a relatively cool fluid such as air which is to beheated for use in heating the interior of a vehicle. Obviously, theinvention may be utilized in the heating or cooling of other fluids andin other connections without departing from the spirit thereof.

It is an object of the present invention to provide an improved heateror heat exchanger for fluids, such as gases, which is compact, eflicientand low in cost.

Another object is to provide a heat exchanger for effecting a transferof heat between two fluids in which the flow of one of the fluids isbroken up to secure an eflective muffler action and in which a maximumof heat transfer is simultaneously assured.

A feature of the present invention comprises a heater or a heatexchanger employing laterally juxtaposed tubes, some of which areperforated and some being imperiorate.

Another feature of the invention resides in a combined heater andmuflier structure utilizing laterally juxtaposed tubes arranged in sets,one set of tubes being imperforate and smaller than the other tubeswhich are perforated.

Still another feature comprises a heat exchanger utilizing three sets oftubes, one of which is angularly disposed with relation to the other twosets of tubes, the latter two sets including individual tubes each ofwhich is capped or closed at one end only and some of these closed endsare located at one end of the heat exchanger and some at the oppositeend.

Another feature comprises a heat exchanger utilizing relatively largeand relatively small tubes passing through a casing, the small tubesbeing interposed between groups of the large tubes and arrangedtransverse thereto and partitions being provided to divide the interiorof the casing into compartments.

These and other important features of the invention and novelcombinations of parts will now be described in detail and then pointedout more particularly in the appended claims.

In the drawings,

Figure 1 is a perspective view of a combination heater or heat exchangerand mufller in the form of a unit embodying the features of the presentinvention and enclosed within a suitable housing with portions of thelatter and the heater broken away;

Figure 2 is a view in elevation with parts broken away of the heatershown in Figure l but with the entire outer housing removed;

Figure 3 is a plan view ofthestructure shown in Fig- 2,759,709 PatentedAug. 21, 19 56 ure 2 with parts of it taken in section along the line3-3 of Figure 2;

Figure 4 is a view in section taken substantially along the line 44 ofFigure 2 with intermediate portions broken away better to illustratecertain tubes;

Figure 5 is a plan view and section similar to that of Figure 3 butshowing a modified form of the invention; and

Figure 6 is a sectional view taken substantially along the line 66 ofFigure 5 with parts broken away.

It has been recognized that in a vehicle such as an army tank or in anautomobile, it is essential that a heater or cooler unit be compact andso proportioned and contoured as to be easily installed with a minimumof space requirements. To this end, a heater embodying the presentinvention is shown in Figure 1 as inclosed within an outer box-likehousing 10. This housing is provided with an opening 12 at its top,through which air to be heated may be admitted, and an opening 14 at oneend through which heated air may be discharged into the vehicle. The airmay be forced through the heater by the action of a fan or by movementof the vehicle. Figure 1 shows a portion of the top of the housing 16]broken away as at 16 for purposes of better illustration, and it is atthis area that the housing is apertured to accommodate a verticalconduit 18. A portion 20 at the other side of the housing 10 is alsobroken away better to show how the heater fits snugly within the housingto make a compact unit and it is to this side of the heater that aconduit 22 is connected.

The heater or heat exchanger, per se, in part comprises a casinggenerally indicated at 24 made up of one piece of sheet metal bent toform four sides, i. e. a top 26, bottom 28, and the two vertical sidesand 32. The ends of the sheet metal forming those sides are caused tooverlap (Fig. 4) and are welded together as at 34.

A number of relatively small, imperforated and parallel tubes 36, whichare open at both ends and herein are considered as the first set oftubes, extend in spaced relation through the casing 24 and the endsthereof project slightly from each of the sides 30 and 32 and aretightly welded thereto as at (Figure 4).

The ends of the casing 24 comprise two plates or tube sheets 42 and 44,the margins of which are in the form of flanges within which the sides26, 28, 30 and 32 are firmly afl'ixed as by welding 46. The plates 42and 44 serve as supports for three tubes 59A, 56B and 59C and threetubes 52A, 52B and 52C which are laterally juxtaposed with relation tothe first set of tubes 36, are relatively larger, and are provided withspaced perforations 54 and 56. The tubes A, 50B and 59C are arranged asa second set of tubes located above or to one side of the first set oftubes 36 and the tubes 52A, 52B and 52C are placed below the tubes as inthe form of a third set of tubes. The two sets of tubes are welded tothe plates 42 and 44 and each is capped at one end by a flanged disc 58or 60 welded thereto. it will be noted that the tubes EtlA, 50B and 50Care capped at the lefthand end of the casing 24 as viewed in Figure 3and that the tubes 52A, 52B and 52C are capped at the opposite end asseen in Figures 2 and 4.

One end of the casing 24 is joined by means of a weld 46 to a header ormanifold 61 which is tapered in two directions as shown in Figures 2 and3 and joined to an enlarged portion 62 having an annular flange 64 towhich the end of the conduit 18 may be aflixed for discharge of fluid. Abaifle plate 66 is vertically placed within the header 6]. dividing thesame into two compartments, one of which is in direct communication withthe conduit 18 and the tube 52C and the other being in directcommunication with the two tubes 52A and 52C. The plate 66 is preferablywelded to the header 61 before assembly with the-main body ofthe heater.No need exists for a tight fit of the plate 66 as incidental directcommunication of the two compartments around theedge or edges of theplate would have no appreciable eifect'on the operation.

Another header 70 is joined to the other end of the easing 24 in thesame manner as shown with respect -to"theheader 61 but in this case, anenlarged portion 72 thereof is located at the diagonally opposite andlower corner of the casing 24 with adownwardly directed flan ga "74 towhich the conduit 22 is affixed for introducing the heatingfluid to theheater. This header 70 has a vertically "disposed baffle plate 76similar to the plate 66 and serves to guide the'fiuid flow whereby fluidfrom conduit 22 is led directly-through the enlarged portion 72 and intothe tube 50A. The paths of the fluid are described more fully'hereinafter.

In order toassist inproperly assembling and maintainmg the heater within.and with relation to the outer housing 10, it has been foundadvantageous to provide a small plate 78 which is generally triangularin shape and is permanently afiixed to the header 71} by welding. The

'so doing, is heated to an elevated temperature and discharged intowhatever compartment or zone of the vehicle it is desired to heat.

Exhaust gases from the vehicle engine are directed by the conduit 22into the enlarged portion 72 and then these gases, except for a minoramount which incidentally may leak by the baffle 76, are guided into oneend of the large .tube 50A which is located just above the outlet of theconduit 22. The baffie plate 76 assures or determines the initial pathof the larger portion of the gases which subsequently emerge from thetube 50A into the space within the casing and surrounding all the tubes.These gases emerge by way of the perforations 54 of the tubev 50A andsome of these flow downwardly and in contact with the outer surfaces ofthe tubes 36 subsequently to enter .the tubes 52A, 52B, and 52C by meansof the perforations 56 therein. The remainder of the gases emanatingfrom the tube 50A is directed toward tubes 50B and 50C.

The latter tubes communicate, because of the header 70,

more evenly to distribute the gases for subsequent effective heatexchange through the tubes 36 with the air flowing through the latter.The gases entering the tube 52A are caused to emerge into the header 61and these gases,

because of the presence of the baffle 66, are for the most partguidedinto the end of the tube 52B. Some of those gases may pass by the edgeof the bafile 66 but this is immaterial. The only outlet from the heaterfor all the exhaust gases is the conduit 18 and, as this is in com- -inthe modification of Figures .2, 3, and 4. Theheader 70 is in.communication with a conduit.22 as is the case of iheader 70 in thepriorfigures. A casing generally indicated at100:is provided and thiscasing is made of sheet-"metal and is similar' in construction to thecasing '4 24 and is made to form four sides or walls, i. e., a top 102,a bottom 104 and two vertical sides 1G6 and 198.

A number of relatively small and imperforated tubes 110 are placed inspaced relation through an intermediate portion of the casing with theends thereof projecting slightly from each of the sides 106 and 108.These tubes 110 form unrestricted passages leading through the casing160 forpassage of air tobeheated.

The casing 100 includes two end plates 112 and 114, the margins of whichare. flanged-and welded in place between the margins'sof the headers 61and 70 and the walls of the casing 100. The plates 112 and 114 serve astube sheets to support such tubes as tubes 116, 118, and 120.Unrestricted passages are provided by those tubes which lead through thecasing 100 and transverse to the tubes 110. Tubes 122 and 124 are alsosupported by the plates 112 and 114 but these tubes are closed or cappedat their endsadjacent or at the plate 112. A sixth'tube .126 is:similarly supported but in this case the tube is closedor'capped at theend which otherwise would be in direct communication with the header 70.As can be seen in Figure 6; tubes 122, 118, and 124 are arranged in theupper portion of the casing 100 and above tubes 110, Whereasthe tubes116, 126, are placed beneath tubes 110. Flanged discs consititute themeans for capping-one endzonly of each of the tubes 122, 124, and 126.Eachiof the six large tubes has perforations-13l spaced; around and.along its length. As both ends of each 'of'theathree tubes 120, 118,and 116 are open, it will be.understood that some of the gases, that is,those not deflected. by the perforations in those tubes, are caused.to:pass axially. through the three tubes in series.

In alignment with" each bafiie 66 and 76 and within the casing 100 isarranged a vertical-partition 132 or 134 and tubes;110 pass1through'these partitions.

In the operation of the structure of Figures 5 and 6 air is causedto;passiaxially through each of the tubes 110 as heretoforetstatedwithregard to the tubes 36 of Figure l and this air is heated by virtueof heat extracted from hot;:gasessintroducedwto the heater from theconduiti22 and as'initially'guidedi'by the baffle 76. The gases firstaxiallyenter both ofthe tubes 120 and 124 because of the open ends thatthey present to the enlarged portion of. the header-70. It is' -notessential that the baffle 76 form a'tightfit:within'the header. Thegases in the tube1124 emerge therefrom through its perforations andcontact the tubes 110 after which they must enter the tube 120through'the-per-forations of the latter and ultimately pass'into the-header 61 because of the presence of the partition 134. These gasesthen are constrained to enter :the' ends of the'tubes 118 and 126leading from the header 61. The 'gases'in thetube '126'emerge laterallytherefrom'by way-of the 'perforations in that tube and, because of thebafiles 132 and 134, these gases sweep over the'middle, portionsof thet'ubes'110 and emerge with the gases already in thetube118 intotheheader 70. These gases then enter' the tubes 116 and 122 by way of theheader' '70 and eventually'discharge from the tube 116 intothe-enlargedportion of the header 61 which communicates with an exhaustconduit ('not shown) similar to conduit 18of Figures -l and 2. "Theenlarged portion in the-header '61 is, as heretofore stated, partiallyde- It will be noted that in the modification of Figures 5 and 6, thoseexhaust gases entering the tubes 124, 126, and'122 are constrained bythe baffles 134 and 132 to make three passes across the tubes'110. Gasesemerging from'theends'ofor' axially through the tubes 120, 118,and1'16'arenotpositively constrained to'pass over the tubes 110 butgases emerging from the ends of tubes 120 and'118 are '"divide'din theheaders 61 and 70 respectively for subsequent contact withthe tubes 110.

We claim:

1. A-'heater"comprising'acasing, a set of parallel and relatively smallimperforate tubes passing through said casing, larger perforated tubespassing through said casing at an angle with said imperforate tubes,some of said larger tubes being open at one end only, and headers atopposite sides of said casing and communicating with said larger tubes.

2. A heater comprising a casing, imperforated tubes forming spacedpassages through said casing, perforated tubes passing through saidcasing at an angle with said imperforated tubes, said perforated tubeseach being open at least at one end, and headers at opposite sides ofsaid casing communicating with said perforated tubes.

3. A heater comprising a casing, a set of imperforated and paralleltubes forming spaced passages through said casing, perforated tubespassing through said casing transverse to said imperforated tubes, someof said perforated tubes being open at one end only and the remainder ofsaid perforated tubes being open at both ends, and headers at oppositesides of said casing communicating with said perforated tubes.

4. A heater comprising a casing, imperforated tubes passing through saidcasing, perforated tubes passing through said casing transverse to saidimperforated tubes, some of said perforated tubes being open at one sideof said casing and closed at the other side, the other perforated tubesbeing open at the said other side and closed at the one side, andheaders at opposite sides of said casing each communicating with theopen ends of said perforated tubes.

5. A heater comprising a casing, imperforated tubes forming spacedpassages through said casing, perforated tubes passing through saidcasing transverse to said imperforated tubes, at least some of saidperforated tubes being open at one end only, headers at opposite sidesof said casing each communicating with the open ends of some of saidperforated tubes, and baffie means in each header.

6. A heater comprising a casing, imperforated tubes forming parallel andspaced passages through said casing, perforated tubes passing throughsaid casing transverse to said imperforated tubes, some of saidperforated tubes being open at one end only, each of the remainingperforated tubes being open at both ends, headers at opposite sides ofsaid casing communicating with said perforated tubes, and bafiie meansin each of said headers.

7. A heat exchanger comprising a casing, a first set of tubes each ofwhich is open at both ends and all passing in one directions throughsaid casing, a second set of tubes, each of which is closed at one end,passing through said casing and located at one side of said first setand transverse thereto, a third set of parallel tubes closed at one endand arranged at the other side of said first set and also passingthrough said casing, said second and third sets of tubes having theirside walls perforated, and means connecting a conduit with the open tubeends of each of the second and third sets.

8. A heat exchanger comprising a casing, a first set of tubes passingthrough said casing, each of said tubes being open at both ends thereof,a second set of tubes, each of which is closed at one end and located atone side of said first set, a third set of tubes, each of which isclosed at one end and located at the other side of said first set, eachtube of said second and third sets being at an angle with the tubes ofthe said first set and having its sides perforated, and means connectinga conduit to each of the second and third sets.

9. A heat exchanger comprising a casing, a first set of imperforatedtubes arranged in said casing to provide passages therethrough, secondand third sets of tubes located at opposite sides of said first set andarranged transverse thereto, the tubes of the said second and third setsbeing perforated and each being closed at one end and open at the other,and means for connecting conduits to the open ends of each of the secondand third sets.

10. A heat exchanger comprising a casing, a first set of tubes arrangedin said casing to provide passages therethrough in one direction, othersets of parallel tubes being arranged transverse to said first set andbeing separated by the latter, said parallel tubes being perforated andeach being open at one end and closed at the other, and a manifold ateach of opposite sides of said casing in communication with thecorresponding open ends of said parallel tubes.

11. A heat exchanger comprising a casing, laterally juxtaposed tubespassing through said casing, some of said tubes being parallel and openat both ends, each of the other tubes being perforated and also beingclosed at one end only, and manifold means connected to the said casingand communicating with the ends of said other tubes to conduct fluidpassing through said perforations.

12. A heat exchanger comprising a casing, a first set of imperforatedtubes passing through an intermediate portion of said casing formingpassages leading therethrough, partitions and other perforated tubes inparallel relation with said partitions arranged within said casingtransverse to said first set of tubes, each of at least three of saidperforated tubes being open at each end and separated from the adjacentone of said three tubes by one of said partitions, each of the other ofsaid perforated tubes being capped at one end only, and manifolds atopposite sides of said casing in communication with said perforatedtubes.

13. A combined heater for air and a mufiier for an engine comprising acasing, a first set of imperforated tubes forming air passages leadingthrough an intermediate portion of said casing, two partitions arrangedtransverse to said imperforated tubes and dividing the interior of saidcasing into three compartments, two perforated tubes within each of saidcompartments, one of said two tubes having only one end open and theother having both ends open, and manifolds at opposite sides of saidcasing and each being in communication with the open end of one of saidperforated tubes leading through each of said compartments.

14. A combined heater and muffler comprising a casing, a first set ofrelatively small and imperforated tubes joined to said casing to formparallel passages leading through an intermediate portion of saidcasing, spaced partitions arranged at right angles to said small tubesand dividing the interior of said easing into compartments, perforatedrelatively large tubes placed in each of said compartments parallel withsaid partitions and passing through two sides of said casing, one ofsaid large tubes in each compartment being open at both ends andtheothers of said large tubes each being open at one end only, and amanifold at each of said two sides forming a chamber enclosing theclosed and open ends of the large tubes passing thereto.

15. A combined heater and mnfiier comprising a sheet metal casing, afirst set of relatively small, spaced, parallel and imperforated tubesleading from one side wall to the opposite side wall of said casing, twopartitions dividing the casing interior into three compartments, each ofsaid partitions being arranged at an angle with said irnperforatedtubes, two perforated relatively large tubes arranged in each of saidcompartments parallel with said partitions, said imperforated tubesbeing interposed between said two large tubes, one of said large tubesin each compartment being open at both ends, the other of said largetubes in each compartment being closed at one end and open at the otherend, the closed end of one large tube in the middle compartment being atone end wall of said casing, the closed ends of the large tubes in theouter compartments being at the opposite end wall of said casing, and aheader connected to each of said end walls for conducting fluid to andfrom said large tubes.

16. A combined heater and mufiier comprising a casing, a first set ofrelatively small imperforated tubes passing through said casing and eachbeing open at both ends thereof, parallel larger and perforated tubeslaterally juxtaposed with relation to said first set and also passingthrough said casing, at least some of said larger tubes being capped atone end, and headers at opposite sides of said casing communicating withsaid larger tubes.

17. A combined heater and mufiler comprising a casing, relatively small,imperforated and unobstructed tubes passing through said casing, largerand perforated tubes laterally juxtaposed with relation to saidimperforated tubes and afiixed to-opposite ends of said casing, at leastone of said larger tubes being capped at one of said casing ends andopen at the other, at least one of said larger tubes being open at bothof said casing ends, and a header at each casing end communicating withthe corresponding open ends of the said larger tubes.

18. A combined heater and mufiier comprising a casing, a first set ofrelatively small, imperforated and unobstructed tubes passing throughsaid casing, larger perforated tubes passing through said casing andopposite ends thereof and laterally disposed with relation to said firstset, some of said larger tubes being closed at one end of said casingand open at the other casing end, some of said larger tubes beingunobstructed, and a manifold at each end of said casing andcommunicating with the corresponding open ends of said larger tubes.

19. A combined heater and muffler comprising a casing, a first set ofrelatively small, imperforated and unobstructed tubes passing throughsaid casing, larger, parallel and perforated tubes passing through saidcasing and the ends thereof and laterally disposed with relation to saidfirst set, at least one of said larger tubes being capped at one end, amanifold at each opposed end of the casing in communication with thecorresponding open ends of said larger tubes, anda baffle in at leastone manifold adapted to channel a major portion of fluid flow throughone of said larger tubes.

20. A combined heater and muffler comprising an oblong casing, a firstset of relatively small, imperforated and unobstructed tubes passingthrough the interior and opposite sides of said casing, larger, paralleland perforated tubes passing through the interior and ends of saidcasing, said larger tubes being arranged transverse to said small tubesand on either side thereof, at least one of said larger tubes beingcapped at one end, a manifold at each opposed end of the casing incommunication with the corresponding open ends of said larger tubes, anda bathe in each of said manifolds arranged to channel a major portion offluid passed therein through one of said larger tubes.

21. A heater comprising a casing, a set of imperforated tubes passing inone direction through said casing for conducting a first fluid, otherperforated tubes passing through the said casing transverse and adjacentto said first set for conducting a second fluid, each of said perforatedtubes being open at least at one end, and headers at opposite sides ofsaid casing communicating with the open ends of said perforated tubes.

References Cited in the file of this patent UNITED STATES PATENTS929,656 Coles Aug. 3, 1909 1,168,136 White Jan. 11, 1916 1,275,465 PetzAug. 13, 1918 1,762,465 Bovey June 10, 1930

